[TrishB]

As usual, Judi W is right! :D

I'd also like to add that it may have been due to you holding her above the other dog. Being "above" is a very dominant place to be. You (unknowingly) placed her in a dominant position over another dog that obviously would have been dominant to her. As a result, she reacted aggressively / fearfully. She didn't have control of the situation, she wasn't able to show her submissiveness to the older dog, so she had to 'display' to confirm that she did in fact deserve to be in that position (over the other dog).

Obviously, she's too young to socialize with strange dogs - but I'm sure that if you had placed her on the ground before the other dog approached - that it would have been a different story! ;)

Thank you so much for rescuing / fostering - be sure to get this little one into puppy classes for socialization! :D